ISLAMIC, 'Abbasid Caliphate. temp. Al-Mahdi, AH 158-169 / AD 775-785. Hemidrachm (Silver, 23 mm, 2.00 g, 3 h), citing the governor of Tabaristan, Umar ibn al-'Ala (AH 154-164 = AD 771-780), Tabaristan, PYE 129 = AH 164 = 780. Crowned and draped Sasanian-style bust to right; behind head, AFZUT GDH ('may his kingship increase' in Pahlawi); before head, 'AWMR' in Pahlawi; in outer margin, APD / NWKW ('excellent' and 'good' in Pahlawi). Rev. Sasanian fire altar set on three steps, flanked by two attending priests (mabedh) standing facing; to left, date; to right, mint TPURSTAN ('Tabaristan' in Pahlawi). Album 56. SICA I, 417. Walker, Arab-Sassanian, p. 139, 275. Good very fine.